keras-team/keras · error · TypeError

Invalid value for `axis` argument: expected an int or a list

Error message

Invalid value for `axis` argument: expected an int or a list/tuple of ints. Received: axis={axis}

What it means

Error "Invalid value for `axis` argument: expected an int or a list/tuple of ints. Received: axis={axis}" thrown in keras-team/keras.

Source

Thrown at keras/src/layers/normalization/unit_normalization.py:34

    >>> normalized_data = keras.layers.UnitNormalization()(data)
    >>> np.sum(normalized_data[0, :] ** 2)
    1.0

    Args:
        axis: Integer or list/tuple. The axis or axes to normalize across.
            Typically, this is the features axis or axes. The left-out axes are
            typically the batch axis or axes. `-1` is the last dimension
            in the input. Defaults to `-1`.
    """

    def __init__(self, axis=-1, **kwargs):
        super().__init__(**kwargs)
        if isinstance(axis, (list, tuple)):
            self.axis = list(axis)
        elif isinstance(axis, int):
            self.axis = axis
        else:
            raise TypeError(
                "Invalid value for `axis` argument: "
                "expected an int or a list/tuple of ints. "
                f"Received: axis={axis}"
            )
        self.supports_masking = True

        self._build_at_init()

    def call(self, inputs):
        return ops.normalize(inputs, axis=self.axis, order=2, epsilon=1e-12)

    def compute_output_shape(self, input_shape):
        # Ensure axis is always treated as a list
        if isinstance(self.axis, int):
            axes = [self.axis]
        else:
            axes = self.axis

View on GitHub (pinned to 7a34a03db6)

When it happens

Trigger: Thrown at keras/src/layers/normalization/unit_normalization.py:34 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of keras-team/keras@7a34a03db6 (2026-08-25). Data as JSON: /api/errors/9b4b6920496e4cee. Report an issue: GitHub.